Ground-leg connection for electrolytic arresters.



E. E. I. GREIGH' ION. GROUND LEG CONNECTION FOR ELECTROLYTIC ABBESTEBS.

APPLIOATIOK FILED JULY 9, 1907.

Patented June 1, 1909.

I I I l I l l J 1 I I l l I I I II 1 l I I I l l-uI lnvmtor Elmer ELF. Creighton J my l I I I l IIL UNITED sTA'jrEs PATENT OEEIOE.

ELMERE. F. CREIGHTON, OF SCHENECTADY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

(mount-LEG CONNECTION FOR ELECTROLYTIC nnnns'rnns.

Specification of Letters Patent.

Patented June 1,-1909.

Application filed July a, 1907: Serial No. 382,860.

To all whom it may concern:

Be it known that I, ELMERE. F. CREIGH- TON, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Ground- Leg Connections for Electrolytic Arresters, of which the following is a specification.

This invention relates to devices for protecting high voltage alternating current transmission lines from the destructive effects of abnormally high Otential charges. What is known as the multiplex connection has been heretofore proposed for this purpose, a lightning arrester being located in a phase-leg between each line conductor and the neutral point of the system, and another arrester in a ground-leg from neutral to earth; so that if any conductor becomes accidentally grounded there will still be the same i number of arresters between line and line as under normal conditions. arrester is in the nature of an emergency device, and is not subjected to the ordinary line voltage.

the system.

the cell in the'ground-leg is not ordinarily in condition to limit a flow of current, O wing to the fact that a cell of this type loses its resisting film when inactive. rl hen brought into service by a ground on one of the lines, this cell requires a brief space of time to become 1 fully operative by the re-forming of its film. f The phase-leg cells are not ordinarily designed to take care of an excess of dynamo potential for a long period, and in order to prevent their overheating by the passage or dynamic current or rapidly recurring surges of high potential current it is highly desirable to provide for a quick re-formation of the film in the auxiliary ground-leg cell.

smaller plates than those in the phase leg. When a ground occurs on any one of the line conductors, the current which flows through the cells has a relatively high value, owing to the large plates in the phase leg and the sudden increase of voltage due to the ground.

This ground-leg i It is called into play only when an abnormally hi 'h potential is impressed on applying aluminum cell or f other electrolytic condenser lightning arl resters to this multiple); connection system,

Other things bein equal, the rapidity of re-formation of the m varies inversely with the area I of the plates and directly with the current.

The present invention consists, therefore, i in providing the ground-leg arrester with i l The cell in the ground leg ofiers practically no resistance, owing to the weakened condition of its film. The cells in both the phase-leg and the ground leg may be damaged unless the current is quickly brought to a lower value than the initial dynamic rush. By us ng smaller plates in the ground-leg cell, this result is accomplished within a safe limit of time.

The accompanying drawing is a diagrammatic representation of the application of my invention to a three phase transmission system.

The three line conductors l, 2, 3 are connected to the neutral point 4 by three phase legs, each containing an electrolytic condenser, 5, 6, 7. Each condenser has sufficient capacity to hold back the normal line vol- 1 tage, While permitting a leakage of small static charges to ground through the ground f leg 8, connected with all the condensers at plates are considerably smaller than those in the main condensers, but the same in num ber. These plates are immersed in an Oil tank. 10 preferably of substantially lllG same size as those containing the nmin condensers so as to gain the advanta e of the quicker cooling ell'ect of the relatively greater volume l. of oil. As no current flows normally through the ground-leg, the films in the cell 9 will be weakened and will offer but little resistance 1 to the assage of small static charges in earth. about the cell 9 to shorten the circuit from neutral to ground under normal conditions of lightningdischarge from lines to earth: but this is not an essential feature of the invention. In case of a ground on any one O! the line conductors, the main condenser connected therewith is short circuiterhand the auxiliary condenser is brought into service. The small plates of this condenser enable the higher potential and increased current to reform the films very quickly, so that the current-limiting effect of the cell is speedily exerted and the dangerous current is sup pressed.

What I claim as new and desire to secure by Letters Patent of the United States, is,

' 1. The combination with the line conductors of a transmission system, of an electrolytic condenser in each phaseleg of the 1 leg contains an auxiliary condenser .l. whose I l multiplex connection, and an auxiliary conthe neutral point of the system, The ground-- f desired, a fuse 11 may he shunted llhl llO.

denser of smaiier capacity in the ground leg of said connection.

2. The combination with the line conductors of a transmission system, of electrolytic condensers connect-ed respectively to each .conluctor and to a common neutral, :1 com- Q mon ground connection from said neutral, and an electrolytic condenser in said ground 1' connection having smeiier plates than those in the other condensers.

3. The combination with the iine conductors of illflnslflliSSiOlWStfiM, of main eleetrolytic' condensers connected respectively! to said conductor and to a common neutral, :1

common ground connection iroln said neu- 15 tral, and an auxiliary electrolytic condenser in said ground connection which requires a less amount of energy the eondenser to reform its In witness whereof, I have hereunto set my 20 hand this 3rddey offluiy, 1907.

\ nnonnienron.

WVitnesses:

BENJAMIN B. HULL,

Onivonn 

